Document U.S. Pat. No. 3,868,262 describes an example of such a method in which all of the aggregate is heated during step (a), which requires a large amount of energy to be used because the initial aggregate mix contains a large quantity of water. In addition, the drying and the temperature being raised result in a large quantity of flue gasses being given off that contain water vapor laden with dust. In view of their large quantity, those flue gases are difficult to treat, and implementing methods of that type therefore gives rise to non-negligible pollution for the environment.